Riparian buffers

Mary Ann Ryan
Adams County Master Gardener

As we become more engaged and educated about our environment, a few words are repeated in our reading and discussions. One of those words is Riparian Buffer.

A riparian buffer is simply an area, or buffer, along a stream or waterway. This buffer is made up of a variety of plants. The best buffers will have trees, shrubs, and herbaceous plants. These plants serve a multitude of important purposes. For example, plants slow down water. As water runs across open land in a heavy rain, it will pick up speed on a surface of open soil, low turf, herbaceous vegetation, or hard surfaces like parking lots and roads. As this water hits larger plants like shrubs and trees, it slows down, allowing that water to filter through the soils prior to hitting the stream.

You may wonder why that matters. As water moves from hard surfaces, like roads, roofs, and open crop land, it picks up sediment, chemicals, oil and other pollutants. Without that buffer zone, all those pollutants will enter the stream, reducing fish life, amphibians and ultimately polluting our food and water sources. The plants in a buffer will filter those pollutants, keeping the streams clean for our wildlife.

Trees also shade the water in the stream. The shade provides the water a lower temperature that will support the life that lives in the stream. The warmer the water, the less that can survive in that water. The shade of the trees helps to control water temperature by reducing the fluctuation of that water temperature.

The roots of the plants, trees in particular, help to reduce the amount of erosion that occurs. Water is very powerful, as we all know. As water runs through the twists and turns of a stream, the power of that water will cause stream banks to erode. Imagine in a heavy rainstorm, water running across an open field or grassy area, with nothing to slow it down, and entering the stream. The more water that enters the stream, the faster it will flow. The faster it flows, the more power it hits against the banks of the twists and turns of the banks. This is why our streams and rivers turn a darker, mucky color after a rainstorm. That water has picked up sediment.

Tree roots help to hold that stream bank in place. The wider the buffer, the better. And the bigger the plants, the better, and of course, diversity of plant life never hurts.

We have a riparian buffer on our property. We’ve been planting trees and shrubs ever since we bought the property in the 90’s. We have river birch and sycamore, maples and willows, oaks, button bush, shrub dogwoods as well as a few chokeberry speckle the understory. Viburnums, winterberry hollies, spicebush, blackgum and, our latest plant introduction on the property, sweetbay magnolia. These are just some of the species in our riparian buffer. This diversity of plant life supports a multitude of insects, birds, amphibians, reptiles, and mammals while continuing to filter water, control erosion, and maintain water temperatures.

Types of plants that may be chosen for a riparian buffer are dependent on the types of soil that exist. Do a little research to find out what the soil texture is (clay, loam, sandy) as well as the soil pH. Plants are particular about these things and may or may not survive the existing environment. Proper plant selection will guarantee success when starting new plants and plant communities. And, choices of plants can determine what types of insects you may have visiting your plant community. For instance, it’s likely you will see spicebush swallowtails if you have spicebush and sassafras living there, as they are a food source for the caterpillars. Therefore, knowing what a food source is for a particular critter may also help in determining what is planted.

Riparian buffers may already exist, or a landowner may be starting from scratch. If a stream has no trees or shrubs growing along thier banks, then enhancement would be extremely beneficial to the water quality, fish life and wildlife depending on it.

Begin by planting trees. Contacting your local Conservation District to enquire about tree seedling sales is a good start. The Conservation District may also know of some programs that will supply you with free tree seedlings to support your efforts. Tree seedlings are inexpensive and have a pretty good survival rate, if planted and managed correctly.

One of the most feasible ways to begin this project is to get bareroot plants. These plants have no soil on the roots, making shipping easier and cheaper. Bareroot plants can be purchased in late winter through early spring, which is also when they need to be planted. When they arrive, whether you have them shipped, or get them from a local supplier, keep the roots wet until you plant them. Keep them wrapped in wet newspaper in a cool location.

When planting them, be sure the hole wide and deep enough to lay the roots out without curling them. Mound the soil in the center of the hole and rest the center of the tree on top of that mound of soil. Lay the roots downward and backfill with the existing soil. Be sure the root flair of the tree is not buried. Only the roots should be underground, not the tree trunk. Tap the soil in and around the roots, filling the hole. Water after planting.

A good next step is to use a tree shelter. Tree shelters will protect the trees from wildlife, like rabbits and deer, until the trees are established. Many types are available, and typically the source that is supplying you with the bareroot trees will have tree shelters for sale as well. When we plant seedlings, we always have tree shelters on them. There’s nothing worse than putting the research and labor into a planting just to have a critter decide that it tastes good! Tree shelters not only provide a physical barrier, but also provides an almost greenhouse environment, allowing the trees to establish quickly.

Once trees are established, little maintenance is needed, but for the first few years, there are some common things that can be done to improve the survival rate of your trees. Check on the trees. Be sure that the tree shelters have not blown off. If they have, just re-install them. You may want to keep weeds and grass pulled away from the base of the trees, and out of the tree shelters. Although the tree shelters, for the most part, protect the seedlings, they also can provide a great habitat for small critters like mice and other rodents. Its warm and there’s a food source, so keeping the weeds out of the shelter will help to reduce the number of critters that may make it their home.

The next time you hear the term riparian buffer, you will know what it is and what it does to support our food and water supply. Know that it plays an important role in our lives. If you have an opportunity to support a riparian buffer project, either in research or labor, consider it. Enjoy what’s around you and know that everything you do impacts our environment. Help to keep it clean and healthy!

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